Compound coke oven battery



April 30, 1963 c. OTTO 3,08

- COMPOUND COKE OVEN BATTERY Filed March 25, 1960 5 s Sheets-Sheet 1 FIG. I.

INVENTOR CARL OTTO A la/M44- ATTORNEYS.

April 30, 1963 c. OTTO 3,087,868

COMPOUND COKE OVEN BATTERY 5 heats-Sheet 2 Filed March 25' 1960 r W NN FIG. 3.

A ril 30, 1963 TTO COMPOUND COKE OVEN BATTERY Filed March 25, 1960 3 Sheets-Sheet 3 'INVENTOR CARL OTTO HUM/@154 AT TORN EYS.

United States Patent s,0s7,sss COMPOUND COKE OVEN BATTERY Carl Otto, 8 The Beachway, Manhasset, NY. Filed Mar. 25, 1960, Ser. No. 17,565 15 Claims. (Cl. 202-135) This invention relates to horizontal coke ovens with vertical heating flues and particularly to improvements in horizontal coke ovens with vertical heating flues of the type known as compound ovens, namely ovens which are adapted to be heated alternatively by rich and lean gas.

The standard horizontal coke oven battery comprises a plurality of elongated ovens which are spaced apart by coke oven heating walls. Each coke oven heating wall includes two spaced liners with vertical lines extending therebetween. The flues may be interconnected in a number of diflerent fashions such as by connecting one flue only with the adjacent flue to thereby render what is commonly known as a hairpin flue oven, or the flues may be so connected that all of the flues distributed along one end of the oven are up flues whereas all the flues on the other end of the oven are down flues to thereby render a two divided oven. There are also what is known as four divided ovens and cross-over ovens, in the latter of which the flues in one heating wall serve as up flues and the flues in the heating wall on the other side of the coke oven chamber serve as down flow flues.

Regardless of which type of flue arrangement is employed all of the conventional types of coke ovens utilize a principle of introduction of air and gas into the bottoms of a plurality of up flow flues in which gas and air combine to burn and thereby yield heat, which passes through the heating wall liners and into the coke oven chambers where it heats the coal charge and converts it to coke. It is always desirable in coking a charge of coal that the charge be coked at a substantially constant rate at all levels of the charge whereby when any portion of the charge is fully coked the remainder thereof is fully coked to thereby make the entire charge ready to be pushed from the coke oven chamber and thereby render the coke oven chamber ready for subsequent recharging.

There are two types of gas which are normally employed in coke ovens for providing the fuel therefor. There is a rich coke oven gas which has a heating value of approximately 500' to 1000 B.t.u.s per cubic foot and a lean coke oven gas which has a heating value of approximately 80 to 150 B.t.u.s per cubic foot. Due to their low heat content lean gases tend to burn comparatively slowly and hence to yield a very long flame, substantially coequal with the full length of the heating flue. To insure full combustion of lean gas, intimate mixture of the gas with combustion air is preferably effected and the path of travel through the up flue must be substantially long to insure complete combustion before the gas changes direction and starts moving either sideways or downward depending on the type of flue construction. Due to the slow burning characteristics of lean gas, there tends to be higher temperatures at the upper end of the flue than at the lower end.

However, when rich gas is employed the gas tends to burn very rapidly and hence yield a short and concentrated flame. This short flame usually results in a very high temperature adjacent the bottom of the flue which is the normal point of introduction of the air and gas into the flue with a sharply reduced temperature adjacent the top of the flue.

There have been a number of attempts to compensate for the bad temperature distribution in rich gas ovens and particularly in gun flue ovens. The most common expedient for overcoming this difficulty has been to step the thickness of the heating Wall liners (stepped wall liners) making the bottom of the liners substantially thicker than the top thereof to thereby retard heat transfer at the bottom as compared with the top to render the temperature in the coke oven chamber substantially constant from bottom to top. While this expedient does work, it will be obvious that :what is being done is to reduce the temperature at the bottom of the coke oven chamber so that it will equal the lower temperature at the top of the coke oven chamber. This, however, is not wholly desirable since the coking rate is dependent upon the temperature. Accordingly, by using this expedient the coking rate may well be lower than can be economically achieved at higher temperatures which are not possible when using the stepped wall liner expedient. Furthermore, the cost of thickening the bottoms of the heating wall liners add to the total cost of the coke oven and,

in addition, subjects the bottom of the heating wall liner to very high temperatures which hastens the deterioration of the fire bricks.

Still another means of achieving uniform heating in rich gas ovens has been the use of the Still or Christmas tree" oven, as exemplified by US. Patent No. 1,901,770, granted to Herman Petsch on March 14, 1933. In these ovens rich gas is introduced at the bottom of the oven and air is introduced at various levels into the heating flue by means of a branched inclined passage through in conventional rich gas ovens.

the binder wall. Thus a portion of the gas will combine with the air at different levels and distribute the combustion along the length of the vertical heating flue and thereby tend to eliminate the hot bottom spots prevalent However, the Still oven has never been adopted in America due to the fact that the air must be passed up to the various levels in the flue by means of a passage in the heating wall binders which passage tends either to weaken the binder and hence the entire coke oven wall structure or to result in a thicker binder wall which results in reduced heat transfer to the charge adjacent the binder and hence unequal coking rate. Moreover, there is no opportunity for regulating the amount of air introduced at various levels which thereby renders the oven a fairly inflexible device which cannot be adapted to dilferent types of rich gas.

In underjet horizontal coke ovens wherein the gas is introduced at the bottom of the oven through steel pipes, the problem of eliminating the hot spot at the bottom of the oven has been reduced by introducing the gas at two levels, that is by providing high and low burners. By utilizing high and low burners the variation in temperature over the height or length of the flue is reduced as there are two vertically spaced heat sources. However, there still remains some variation in temperature. Moreover, the expedient of high and low burners has never been successful in gun flue ovens due to the fact that the rich gas passing to the upper burner is cracked due to the high temperatures at the bottom of the oven to thereby yield carbonization and the depositing of gums and resins at the high burner which clog the burner and reduce the heating value of the gas.

An excellent discussion of these problems is presented in an article entitled Wilputte Issues a White Paper, by Louis Wilputte, May 1939 issue of Blast Furnace and Steel Plant Magazine.

In my US. patent application Serial No. 10,606 filed by me on February 24, 1960, for Improved Heating Horizontal Coke Ovens With Vertical Heating Flues, I disclosed a novel means for achieving uniform heating in rich gas ovens. This uniform heating is achieved by introducing the rich gas in substantially solely a vertical direction at the bottom of the flue and introducing the combustion air in substantially solely a vertical direction at the bottom of the flue and at a point considerably above the bottom of the flue. The streams of air are parallel to the stream of gas and are horizontally spaced therefrom and tend to admix slowly with the gas whereby to inhibit combustion and thereby elongate the flame. By utilizing this means of achieving uniform heating the stepped liner construction commonly employed to achieve uniform heating can be eliminated to thereby yield a liner wall of substantially uniform thickness and of a thickness considerably less than that used in stepped liner constructions. The reduction in thickness of the liner walls will yield either a higher coking rate or will permit a lower flue temperature for the same coking rate.

While my novel construction for achieving uniform heating in rich gas ovens is excellently adapted for the purposes described, if the same expedient without modification is employed with lean gas, the length of the lean gas flame will be so extended that the gas will not be entirely consumed during its upward passage through the up flues thus yielding a highly undesirable result of either incomplete utilization of fuel or the burning of the gas in the down flues. The present invention is directed to a coke oven construction which will operate when burning rich gas in the manner described in connection with my aforementioned copendin g application but which will operate with lean gas in such a manner as to insure complete combustion of the lean fuel during the passage of the lean gas through the up flue and to provide for uniform heating with lean gas as well as with rich gas.

The main object of the present invention is the provision of a new and improved compound horizontal coke oven which will provide for substantially uniform combustion throughout the vertical length of the heating flues regardless of whether rich gas or lean gas is being burned.

Still another object of the present invention is the provision of a new and improved compound horizontal coke oven which will provide substantially uniform heating along the entire vertical extent of the heating wall regardless of whether rich gas or lean gas is being burned.

Yet another object of the present invention is the provision of a new and improved compound horizontal coke oven having heating wall liners of substantially uniform thickness throughout the height thereof, and with gas and air introducing means disposed within the flues between the liners which are arranged to elongate a rich gas flame to render the heating within the heating walls substantially uniform when rich gas is being burned and to insure complete and substantially uniform combustion of lean gas to thereby render the heating substantially uniform throughout the height of the heating wall when lean gas is being burned.

In accordance with the present invention, I provide a coke oven battery having a plurality of coke oven chambers spaced apart by heating walls. Each heating wall is made of two liners of substantially uniform thickness throughout the vertical length thereof with a plurality of flues disposed between the heating wall liners. In each flue I provide a rich gas opening at the bottom of the flues for introducing rich gas in substantially solely a vertical direction. I also provide means remote from the rich gas opening for introducing combustion air into the bottom of the flue in substantially solely a vertical direction. A portion of the opening for the combustion air is overlied by a chimney disposed in the flue for conducting some of the combustion air to a higher level for introduction at that level in substantially solely a vertical direction. Accordingly, during rich gas operation a stream of air is introduced into the bottom of the flue and at a higher level, both streams moving substantially parallel in solely a vertical direction. Thus the air and gas moving up alongside of the chimney will admix slowly and thereby retard the combustion. Moreover, slow admixing will continue beyond the upper end of the chimney when the second stream of combustion air is introduced to continue a steady combustion of the rich gas throughout substantially the full height of the oven,

When lean gas is employed the rich gas introducing means is rendered inoperative and the lean gas is mixed with the combustion air just prior to their introduction at the bottom of the flue to thereby insure combustion of the introduced lean gas and combustion air. Moreover, additional lean gas and combustion air are permitted to flow into the chimney and to mix in the chimney and commence burning inside the chimney so as to insure that the additional lean gas moving upwardly through the chimney will be practically fully consumed by the time it reaches the top of the flue. With the lean gas burning in the chimney, the chimney will become extremely hot and will serve to radiate heat to the bottom of the liners to thereby tend to equalize the temperature throughout the flue during lean gas operation. Means are provided to adjust the openings at the bottom of the flue and at the top of the chimney, which means will serve to adjust the amounts of mixed lean gas and combustion air introduced at the bottom of the flue and into the chimney during lean gas operation and the amounts of combustion air introduced during rich gas operation, whereby to insure uniform heating when either rich gas or lean gas is being burned.

The above and other objects, characteristics and features of the present invention will be more fully understood from the following description taken in connection with the accompanying illustrative drawings.

In the drawings:

FIG. 1 is a longitudinal sectional view of a coke oven battery embodying the present invention;

FIG. 2 is a sectional view taken along the line 2--2 of FIG. 4;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2;

FIG. 4 is a sectional view taken along the line 4-4 of FIG. 2; and

FIG. 5 is a sectional view taken along the line 5-5 of FIG. 1.

FIGS. 1 and 5 generally illustrate a horizotnal coke oven battery 10 of well known general construction comprising alternating heating walls 12 and coking chambers 14, and regenerator chambers 15, 16, '17 and 18, below the level of said coking chambers and heating walls. The coke oven battery structure 10 is of the well known hairpin flue type of horizontal regenerative coke oven battery adapted for burning both rich gas and lean gas; that is, the coke oven battery is of the compound type. Although battery 10 as illustrated is of the hairpin flue type, other types of flue arrangements may be employed in accordance with the present invention such as, for instance, two divided ovens, four divided ovens and crossover ovens. In the hairpin flue type oven each of the heating flues '12 are formed with numerous non-connected pairs of vertical flues 20 and 22, the two flues of each pair being connected at the upper ends by passages 24.

A brickwork layer 26 directly beneath the heating walls 12 and coking chambers 14 forms the deck or floor for said heating walls and coking chambers and the roof of the plurality of regenerator chambers 15, 16, 17 and 18.

Vertical pillar walls 27 separate regenerator chambers 15 from their adjacent chambers 16, vertical pillar walls 28 separate regenerator chambers '16 from adjacent regenerator chambers 17, vertical pillar walls 29 separate regenerator chambers 17 from adjacent chambers 18 and vertical pillar walls 30 separate regenerator chambers 18 from their adjacent chambers 15. The regenerator chambers 15, 16, 17 and 18 extend across the battery from one side to the other but are divided into end to end sections by walls 25. Excepting the endmost regenerator chambers, each regenerator chamber 15 is connected to a flue 20 by a passage 31 through the deck 26 and is connected to a flue 22 by a passage 32; each regenerator chamber 16 is connected to a flue 20 by a passage 33 through deck 26 and is connected by a passage 34 to a flue 22; each regenerator chamber 17 is connected to a flue 20 by a passage 35 and to a flue 22 by a passage 36; each regenerator chamber 18 is connected to a flue 20 by a passage 37 through the deck 26 and is connected to a flue 22 by a passage 38 through said deck.

Each heating wall 12 is made up of two spaced vertical brickwork liners 42 and 44 between which extend the hairpin flues 20 and 22 and the connecting passages 24. To define the flues 20 and 22 and the passages 24 vertically extending binder walls 46 and 48 extend between the brickwork liners 42 and 44 at spaced intervals to divide the space between the liners 42 and 44 into the flues 20 and 22. As seen in FIG. 5 the walls 46 do not extend to the tops of the flues but are spaced apart therefrom to provide for the passages 24 and the walls 48 extend to the top of the flues to separate one pair of hairpin flues 20-22 from the adjacent pairs thereof. In accordance with one feature of the present invention each of the brickwork liners 42 and 44- is substantially of uniform thickness throughout save for the bottommost courses of bricks not exceeding about three of standard dimensions in number, but here shown as only one in number, which bottommost courses are thickened to provide for erosion resistance to the action of the pusher. As will be obvious to those skilled in the art, substantially uniformly thick liners 42 and 44 are far more simple to construct than are the stepped liners heretofore employed. It will further be understood as this description proceeds that the use of the uniformly thick liners 42 and 44 can only be effectuated provided the burning or heating in the flues 20' and 22 is substantially uniform throughout the height thereof. As will be shown hereinafter such uniform heating is achieved by the present invention under both lean gas and rich gas operation. It will be understood that the term uniformly thick liners or substantially uniformly thick liners, it is meant to convey that the liners 42 and 44 are substantially uniformly thick above about the third course of bricks of standard height of about four and one half inches forming said liners. This is to be contrasted with conventional stepped wall liner construction wherein the wall is divided into three sections of, for instance, six inches, five inches and four inches thickness. Notwithstanding this, however, minor variations in thickness of the wall liners made in accordance with the present invention above about the third course of bricks will not render a wall not substantially uniformly thic As has been pointed out hereinbefore, the bottommost course must be somewhat thicker than the remainder of the wall. If desired, up to about the bottom three courses of standard sized bricks (4 /2 inches high) may be made somewhat thicker.

As shown herein, when the battery is operated on rich gas, the rich gas is supplied to the lower ends of the flues 20 and 22 by means of gun flues 50 and 52 which are disposed in the brickwork deck 26 and extend beneath the liners 42 and 44, respectively. The positioning of the gun flues under the liners rather than under the heating flues themselves, as is usual, permits the passages 3-1 to 38, inclusive, to extend straight upward into the flues 20 and 22, respectively, instead of around the gun flues as is usual construction. This form of construction aids in introducing the combustion air during rich gas operations in a straight upward path which is advantageous as will become apparent hereinafter. Branching off at spaced intervals from each gun flue 50 are inclined passages 54 for conveying gas from the gun flue 50 to vertically directed nozzles 56 which are located at the bottoms of the flues 20 and 22 along one side thereof. As shown herein the nozzles 56 are each centrally located with respect to the width of the flues '20 and 22 although this is not absolutely necessary to the present invention. Branching off at spaced intervals from each of the gun flues 52 is a plurality of inclined passages 58 for conveying rich gas from the gun flues 52 to nozzles 56 disposed at the bottoms of the flues 20 and 22. Each of the nozzles 56 is oriented to introduce the rich gas into the respective flues in a substantially solely vertical direction. It will be understood as is common practice that during rich gas operation, gas is alternately fed to the gun flues 50 and 52 depending upon the flow of heating products through the flues 20 and 22. In the event that air and gas is moving upwardly through the heating flues supplied by gun flues 50 and downwardly through the heating flues supplied by gun flues 52, then rich gas is fed to the nozzles by means of the gun flues 50 and at that time no gas is flowing through the gun flues 52. When the flow is reversed, gas ceases to flow through the gun flues 50 and gas is supplied through the gun flue 5 2 to the nozzles. Naturally, during lean gas operation no gas will be supplied to the gun flues or to the nozzles 56. Although the gun flue construction is preferred the present invention can also be practiced with other constructions such as that commonly known as an underjet oven.

As stated hereinbefore, one of the objects of the present invention is to provide means for greatly elongating the flame in the flues resulting from the combustion of rich gas and combustion air in order to achieve substantially uniform heating throughout the vertical length of the flues. With the uniform combustion of the rich gas throughout the vertical length of the flues the liner walls 42 and 44 may be of substantially uniform thickness throughout rather than made of stepped design. The use of substantially uniformly thick liner walls 42 and 44 makes the coke oven more simple to build and also yields either a higher coking rate or a lower heating wall temperature, the latter of which results in an increase in the life of the liner walls. The means for achieving these desirable ends are illustrated in detail in FIGS. 2, 3 and 4. Referring now to these figures, the dividers 39, 41, 43 and 45 which separate the passages 31 through 38 from one another have their upper ends all terminating just below the top of the deck 26 so that adjacent pairs of passages 3 1--33, 32-34, 35-37 and 36-'38 communicate with the flues 20 and 22 in substantially broad T-shaped openings 62. These openings extend across the central portions of the flues 20 and 22 whereby to provide a substantial spacing between the nozzles and the openings. Overlying the legs 67 of the T-shaped openings 62 in the flues 20 and 22 are chimneys 66 which have central passages 68 extending therethrough. Passages 68 are in communication with the merged openings 62 formed by the ends of the passages through the deck 26 whereby to convey gaseous material flowing upwardly through the deck passages to a higher level in the flues 20 and '22. For instance, in a typical coke oven construction wherein the vertically extending flues 2d and 22 are approximately eleven feet in height the tops of the chimneys may be approximately two feet above the deck 26. To support each chimney in overlying relation with the leg of the T-shaped openings 62, two bricks 63 and 65 are provided. These bricks are flush with the top of deck 26 and underlie portions of the chimney wall to sup-port said chimney.

With the chimneys 66 overlying only the leg of the merged T-shaped openings 62 at the bottoms of the flues 20 and 22 the cross-parts of the T-shaped merged openings, designated by the reference character 70, remain uncovered and free to expell gaseous material into the bottoms of the flues 20 and 22. This gaseous material will be introduced into the flues in substantially solely vertically directed non-turbulent streams.

As is generally known by those skilled in the art, in a compound oven the passages through the deck 26 from the regenerators to the heating flues are so arranged that when the heating flues 20 in one heating wall are serving as up flues the heating flues 20 in the next adjacent heating wall serve as down flues. Moreover, in rich gas operation the rows of regenerators operate in tandem to supply combustion air to the flues. That is, during onehalf of the cycle of operation air is introduced upwardly through the regenerators 15 and 16 and the waste gas is removed from the down flues through the regenerator chambers 17 and 18. Hence, in rich gas operation, during the half of the cycle when the gun flues 50 supply rich gas to the up flues the rich gas will be introduced through the nozzles 56 and 60 at the bottoms of the up flues 20 and 22, respectively, combustion air will be introduced through the regenerator chambers 15 and 16, to the up flues, and the waste products will pass out of the down flues through the regenerator chambers 17 and 18. The rich gas is introduced through the nozzles in substantially solely a vertical direction along one side of the up flues. The combustion air will be introduced at two points. One of the points is through the crosspart 70 of the T-shaped opening 62 at the bottom of the heating flues and the second point will be at the top of the chimneys 66 in the up flues. The two streams of combustion air are substantially solely vertically directed and are preferably non-turbulent whereby to yield a laminar flow. The stream emanating from the opening 62 more or less moves upward along the front of chimney 66 whereby to provide further a laminar flow of gas and air which will slowly admix to thereby retard combustion. Further, as will be described in greater detail hereinafter, there will be insufficient air introduced at the bottoms of the up flues to fully oxidize the rich gas which will further serve to lengthen the flame. When the gas and air introduced at the bottom of the flue, and the reaction products therefrom, pass the tops of the chimneys, the second stream of combustion air will commence moving upwardly through the up flues in a non-turbulent laminar fashion and will slowly admix with the unreacted and partially reacted rich gas to continue the burning thereof. By proper proportioning of the volume of air introduced at the bottoms of the flues and through the tops of the chimneys, the rich gas can be burned throughout substantially the full length of the flues in a uniform fashion to thereby render uniform heating throughout the entire vertical length of the flue.

Naturally, at the end of one half of the cycle of operation, the flow of air and gas is reversed so that the up flues during the first half of the cycle become down flues and the down flues during the first half of the cycle become up flues. To effect the reversal in addition to changing the direction of flow through the regenerator chambers 15, 16, 17 and 18, the gun flues 50 are turned off and the gun flues 52 are turned on so that rich gas will be introduced into the appropriate flues for reverse operation.

In accordance with another constructional feature of the present invention, means is included for regulating the total amount of combustion air introduced into each flue during rich gas operation and for regulating the relative proportions of said combustion air introduced into the bottoms of the flues and at the tops of the chimneys. As shown herein these regulating means are sliding bricks. Referring to FIGS. 2, 3 and 4, at the bottom of each flue 20 and 22 are two sliding bricks 74 and 76, which are adapted to adjust the size of the opening in the bottom of the flue, that is the opening 70. Further, a sliding brick 78 is slidably disposed at the top of the chimney for adjusting the opening size therein. Thus, by properly locating the position of the sliding bricks, the size of the opening 70 as well as the size of the opening at the top of the chimney 66 can be regulated to thereby regulate both the total volume of air and the distribution of air emanating from the two openings. If desired, regulation of the total volume of air can further be achieved by preselection of the size of the openings 62, or by means of a sliding brick located near or at the top of the flues 20 or 22 or in the passages 24.

From the above discussion it will be seen that means are provided for retarding the combustion of rich gas when my compound oven is operating on rich gas. By

retarding the combustion the rich gas flame is elongated to thereby provide for substantially uniform heat. However, when lean gas is to be used in the battery if the combustion of the lean gas were retarded, due to the slow burning characteristics of lean gas, the lean gas would not be fully burned by the time it reached the top of the up flues and would continue burning as it passed through the down flues which is undesirable.

As those skilled in the art understand, lean gas is generally introduced into a compound oven through the regenerator chambers themselves. What is commonly done is that combustion air is introduced through, for instance, the regenerator chambers 15 and the lean gas is introduced through the regenerator chambers 16, with the waste products being removed through regenerator chambers 17 and 18. During reverse operation combustion air is introduced through the regenerator chambers 17, lean gas is introduced through regenerator chambers 18 and the waste products are removed through regenerator chambers 15 and 16. Thus both the combustion air and lean gas are preheated during lean gas operation. To overcome the difliculties of too long a flame during lean gas operation in the oven of my construc tion the oven is so arranged that during lean gas operation, the lean gas and combustion air are intimately mixed close to the bottom of the heating flues to insure complete combustion prior to the gaseous materials reaching the tops of the up flues. This is accomplished by having the dividers 39, 41, 43 and 45 terminate below the top of the deck 26. Connected to the tops of the dividers may be partition extensions which extend a short way up into the leg 67 of the T-shaped openings 62, preferably not further than to the bottoms of chimneys 66. Naturally, while the partition extensions 80 will maintain lean gas and air flowing into the chimney separate until the lean gas and air pass the tops of the partition extensions, the lean gas and air flowing out through the cross-parts 70 of the openings 62 will have an opportunity to admix between the tops of the dividers and the top of the deck so that they can commence or be burning as they are introduced into the bottoms of the heating flues. Moreover, as soon as the lean gas and air pass the tops of the partitions 80, they too will admix and commence burning within the chimney. The chimney is sufficiently thin that it will not retard heat transfer a great deal so that the heat generated by combustion within the chimney will contribute to the overall heating in the flues. A chimney wall thickness of approximately three quarters of an inch to about one inch made of silica brick will give satisfactory results. With the lean gas burning throughout substantially the full length of the chimney, the chimney itself will become hot and will serve to radiate heat to the bottoms of the liner walls. Hence, the presence of the chimneys during lean gas operation will tend to increase the heat at the bottoms of the heating flues to thereby equalize the temperatures throughout the entire length of the heating flue. This equalization is due to the fact that in ordinary compound ovens without my novel construction the lean gas burns slowly and with a pale blue flame and the rate of heat transfer to the liner walls is low. Hence, the heat from the slow reaction tends to rise to the tops of the heating flues to thereby raise the temperatures at the tops and leave the bottoms relatively cool. However, with the chimneys themselves acting as radiators at the bottoms of the flues the temperature during lean gas operation will be substantially uniform throughout. The combustion of the lean gas and air introduced both at the bottoms of the flues and the tops of the chimneys is naturally a slow reaction and will continue throughout substantially the full length of the flue to thereby render substantially uniform burning and a substantially uniform temperature during lean gas operation.

The inclusion of the partitions 80, although preferable, is not necessary. If desired the mixing of the lean gas and air during lean gas operation can commence below the chimney in the zone between the tops of the dividers 39, 41, 43 and 45 and the top of the deck 26. Hence, the partition can be eliminated if desired. Also, if it is found that the elimination of the partitions 80 results in the lean gas flame being too short to thus result in relatively cool tops in the heating flues, the partitions 80 may be included and may even be extended a short distance up into the chimney passages 68 themselves to retard the combustion of the lean gas and air passing through the chimneys and thereby lengthen the flame. However, in working my invention it is important that combustion of the lean gas take place throughout a substantial part of the length of the chimney to thereby heat the chimney walls so that the chimney will act as a radiator to equalize temperature throughout the heating flues during lean gas operation. If desired, to promote combustion of the lean gas and air in the chimneys, a suitable mixing means may be disposed at or near the bottoms thereof just above the partitions 80 if such partitions are included. The mixing means may be a stationary spiral vane made of highly refractory material such as silica brick or it may be a refractory rotary blade or the like. In any event, such inclusion of a mixing means of the type described will insure intimate mixing of the air and lean gas in the chimneys during lean gas operation to thus insure .a substantial degree of combustion of the lean gas as it passes upwardly through the chimneys 66. Moreover, with the mixing means disposed adjacent the bottoms of the chimneys, they will not interfere with rich gas operation, for, during rich gas operation, there will be a sufiicient distance for the mixed air to flow through the chimney after passing the mixing means that the flow will once again become comparatively streamlined. Accordingly, when the air is introduced into the flues at the tops of the chimneys it will slowly admix with the rich gas during rich gas operation and thus yield the retarded combustion of the rich gas.

In lean gas operation air is introduced into the up flues 20 and 22 through the regenerator passages and lean gas is introduced through the regenerator passages 16. The gun flues are inoperative at this time. Hence, combustion will take place at or near the bottom of the flues and at or near the bottom of the chimneys to thereby render a lean gas flame of proper length. The products of combustion will flow through the passages 24 and through the down flues 22 and 20, respectively, and out through the regenerator passages 17 and 18. After half the cycle of operation is completed, which half cycle is usually of about one-half hour in duration, the flow is reversed and combustion air will be introduced into the up flues 20 and 22 (which were previously down flues) through the regenerator passages 17, and lean gas will be introduced into the said up flues through regenerator passages 18. Combustion will start again at or near the bottoms of the up flues and at or near the bottoms of the chimneys to yield a substantially uniform heating of the lean gas throughout the vertical length of the up flues and the products of combustion will pass through the passages 24 and down through the down flues 22 and 20, respectively, and out through the regenerator chambers 15 and 16. Naturally, when the battery is changed over to rich gas construction, then only combustion air is introduced through the regenerator chambers, the rich gas being introduced through the gun flues and ultimately through the nozzles 56 and 60 at the bottoms of the up flues. The description of the operation of the battery on rich gas has been presented hereinbefore and a further description thereof is believed to be unnecessary.

Hence it will be seen that by utilizing the features of the present invention, the flame resulting from the combustion of rich gas in my compound oven will be elongated by retarding the combustion by means of the introduction of rich gas at the bottoms of the flues and the air at vertically spaced levels and in vertical laminar nonturbulent streams whereas the flame resulting from the combustion of lean gas will not be elongated due to the intimate admixing of the lean gas and air at or near the bottoms of the flues and at or near the bottoms of the chimneys. Moreover, on lean gas operation combustion will take place in the chimney to thereby cause the chimney to act as a radiator and thus increase the temperature in the area of the bottoms of the flues to reduce the tendency of compound ovens to have cool flue bottoms on lean gas operation. Accordingly, for either rich gas or lean gas operation the burning will take place at a substantially uni-form rate throughout approximately the entire vertical length of the up flues to insure substantially uniform heating throughout said vertical length.

With the substantially uniform heating throughout the height (or vertical length) of the flues, the substantially uniformly thick wall liners 42 and 44 may be employed. The thickness of these wall liners may be equal to the minimum thickness of previously used stepped wall liners, approximately four inches, in which event, if the same amount of gas is consumed as in conventional coke oven batteries, the temperature within the coke ovens will be higher to thus yield a more rapid coking of the coal charge or the amount of fuel consumed may be reduced to reduce the temperature in the coking chamber to that normally encountered in present day ovens to thus yield a coking rate the same as is presently achieved but with less fuel and with lower flue temperatures. As the deterioration of the liner walls is dependent in part on temperature, the life of the liner walls under the reduced temperature conditions will be substantially increased.

For example, in a present day conventional gun flue hairpin compound even having standard stepped liner walls of the dimensions six inches thick at the bottom, five inches thick in the middle and four inches thick at the top, to maintain the present day standard coking rate of one inch per hour in a seventeen inch wide oven, during rich gas operation it is necessary to have the temperature rat the bottom of the flue approximately 1420 C., which results in the temperatures at the middle of the flue being about 1350" C. and at the top of the flue 1280 C. With these flue temperatures in a stepped liner wall construction the temperature on the oven side of the liner walls will be uniformly about 1000 C. and this will yield the standard coking rate of about one inch per hour.

However, in an oven of my novel construction as described herein, and having substantially uniformly thick liner walls of about four inches thickness, if the maximum temperature in the flue is maintained at the same level as the maximum temperature in the flue of a conventional oven, namely 1420 C., the temperature throughout the flue in my oven will be approximately 1420 C. to thereby yield a substantially uniform temperature of about 1070" C. on the coke oven chamber side of the uniformly thick liner walls. This higher coke oven chamber temperature will result in a faster coking rate, which increased coking rate will result in a reduction in coking time in a seventeen inch coking chamber of about an hour and a half.

In the alternative, in .a coke oven battery of my novel construction, the coking rate can be maintained at the standard value of one inch per hour by lowering the maximum temperature in the heating flues. I have found that to maintain the temperatures on the coking chamber side of the liner walls at 1000 C., the maximum temperature inside the heating flues, assuming substantially uniformly thick liner walls of four inches, will be only about 1280 C., resulting in a net reduction of heating flue temperature of about C. This substantial reduction in heating flue temperatures will result in a substantially longer life for the wall liners and in a saving in fuel.

While I have herein shown and described the preferred form of the present invention, it will be understood that various changes and modifications can be made therein 11 within the scope of the appended claims without departing from the spirit and scope of this invention.

What I claim is:

1. In a compound coke oven battery having a plurality of spaced apart coking chambers :and a plurality of heating walls disposed therebetween, each of said heating walls having a multiplicity of vertically extending heating flues therewithin, and a deck underlying said heating walls and coking chambers; the combination with substantially each of said heating flues of a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, one of said pair of passages being adapted to supply lean gas to said heating flue and the other of said passages being adapted to supply combustion air to said heating flue, a chimney in said flue, said chimney having a top opening disposed substantially above the bottom of said flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas and combustion air to a level substantially above the bottom of said flue and for introducing said mixed gas and air and their combustion products into said flue at said higher level through said top opening, and a third passage through said deck opening into the bottom of said flue at a point horizontally offset from said first mentioned deck opening, said third passage being adapted to supply r-ich gas to said heating flue.

2. In a compound coke oven battery having a plurality of spaced apart coking chambers and a plurality of heating walls disposed therebetween, each of said heating walls having a multiplicity of vertically extending heating flues therewithin, and a deck underlying said heating Walls and coking chambers; the combination with substantially each of said heating flues of a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, said deck opening being adapted to pass gaseous fluid therethrough in substantially solely a vertical direction, one of said pair of passages being adapted to supply lean gas to said heating flue and the other of said passages :being adapted to supply combustion air to said heat-ing flue, a vertically extending chimney in said flue, said chimney having a top opening disposed substantially above the bottom of said flue, the bottom of said chimney overlying a port-ion only of said opening in said deck for conveying mixed lean gas, air and their combustion products to a level substantially above the bottom of said flue and for introducing said mixed gas and air and combustion products therefrom into said flue at said higher level through said top opening in substantially solely a vertical direction, and a third passage through said deck which opens into the bottom of said flue at a point horizontally ofiset from said first mentioned deck opening, said third passage being adapted to supply rich gas to said heating flue in substantially solely a vertical direction.

3. The combination defined in claim 2, further comprising means for regulating the size of said first mentioned opening and said top opening in said chimney.

4. In a compound coke oven battery adapted to operate alternatively on rich gas and on lean gas, said coke oven battery having a plurality of spaced apart coking chambers and a plurality of heating wa-lls disposed therebetween, each of said heating walls having a multiplicity of vertically extending heating flues therewithin, and a deck underlying said heating walls and coking chambers; the combination with substantially each of said heating flues of a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, one of said pair of passages being adapted to supply lean gas to said heating flue during lean gas operation and to supply air to said heating flue during rich gas operation, the

other of said pair of passages being adapted to supply air to said heating flue during both lean gas and rich gas operation, a chimney in said flue, said chimney having a top opening disposed substantially above the bottom of said flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas and air to a level substantially above the bottom of said flue and for introducing said mixed lean gas and air and their combustion products into said flue through said top chimney opening during lean gas operation and for conveying air to said level substantially above the bottom of said flue and for introducing said air into said flue through said top chimney opening during rich gas operation, and a third passage through said deck which opens into the bottom of said flue at a point horizontally offset from said first mentioned opening, said third passage being adapted to supply rich gas to said flue during rich gas operation.

5. In a compound coke oven battery adapted to operate alternatively on rich gas and on lean gas, said coke oven battery having a plurality of spaced apart coking chambers and a plurality of heating Walls disposed therebetween, each of said heating walls having a multiplicity of vertically extending heating flues therewithin and a deck underlying said heating walls and coking chambers; the combination with substantially each of said heating flues of a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, said deck opening being adapted to pass gaseous fluid therethrough in substantially solely a vertical direction, one of said pair of passages being adapted to supply lean gas to said heating flue during lean gas operation and to supply air to said r heating flue during rich gas operation, the other of said pair of passages being adapted to supply air to said heating flue during both lean gas and rich gas operation, a vertically extending chimney in said flue, said chimney having a top opening disposed substantially above the bottom of said flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas, air and their combustion products to a level substantially above the bottom of said flue and for introducing said mixed lean gas, air and combustion products into said flue through said top chimney opening during lean gas operation and for conveying air to said level substantially above the bottom of said flue and for introducing air into said flue through said top chimney opening in substantially solely a vertical direction during rich gas operation, and a third passage through said deck which opens into the bottom of said flue at a point horizontally offset from said first mentioned opening, said third passage being adapted to supply rich gas to said flue in substantially solely a vertical direction during rich gas operation.

6. The combination defined in claim 5, further comprising means for regulating the size of said first mentioned deck opening and said top opening in said chimney.

7. A compound coke oven battery, comprising a plurality of spaced apart heating walls with a plurality of coking chambers disposed therebetween, each of said heating walls including a pair of spaced apart substantially uniformly thick heating wall liners with a multiplicity of vertically extending heating flues therebetween, a deck underlying said heating walls and coking chambers, substantially each of said heating flues having associated therewith a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, one of said pair of passages being adapted to supply lean gas to said heating flue and the other of said passages being adapted to supply combustion air to said heating flue, a chimney in said flue, said chimney having a top opening disposed 13 substantially above the bottom of said flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas, air and their combustion products to a, level substantially above the bottom of said flue and for introducing said mixed gas and air and combustion products into said flue at said higher level through said top opening, and a third passage through said deck opening into the bottom of said flue at a point horizontally offset from said first mentioned deck openings, said third passage being adapted to supply rich gas to said heating flue.

8. A compound coke oven battery adapted to operate alternatively on rich gas and on lean gas, said coke oven battery comprising a plurality of spaced apart heating Walls with a plurality of coking chambers disposed therebetween, each of said heating walls including a pair of spaced apart substantially uniformly thick heating wall liners with a multiplicity of vertically extending heating flues therebetween, a deck underlying said heating walls and coking chambers, substantially each of said heating flues having associated therewith a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, one of said pair of passages being adapted to supply lean gas to said heating flue during lean gas operation and to supply air to said heating flue during rich gas operation, the other of said pair of passages being adapted to supply air to said heating flue during both lean gas and rich gas operation, a chimney in said flue, said chimney having a top opening disposed substantially above the bottom of said flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas, air and their combustion products to a, level substantially above the bottom of said flue and for introducing said mixed lean gas, air and combustion products into said flue through said top chimney opening during lean gas operation and for conveying air to said level substantially above the bottom of said flue and for introducing said air into said flue through said top chimney opening during rich gas operation, and a third passage through said deck opening into the bottom of said flue at a point horizontally offset from said first mentioned opening, said third passage being adapted to supply rich gas to said flue during rich gas operation.

9. A compound hairpin flue coke oven battern adapted to operate alternatively on rich gas and on lean gas, said coke oven battery comprising a plurality of spaced apart heating walls with :a plurality of coking chambers disposed therebetween, each of said heating walls including a pair of spaced apart substantially uniformly thick heating wall liners with a multiplicity of vertically extending heating flues therebetween, a deck underlying said heating walls and coking chambers, substantially each of said heating flues having associated therewith a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, said deck opening being adapted to pass gaseous fluid therethrough in substantially solely a vertical direction, one of said pair of passages being adapted to supply lean gas to said heating flue during lean gas operation and to supply air to said heating flue during rich gas operation, the other of said pair of passages being adapted to supply air to said heating flue during both lean gas and rich gas operation, a vertically extending chimney in said heating flue, said chimney having a top opening disposed substantially above the bottom of said heating flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas and air to a level substantially above the bottom of said heating flue and for introducing said mixed lean gas, air and their combustion products into said heating fiue through said top chimney opening during lean gas operation and for con veying air to said level substantially above the bottom of said heating flue and for introducing said air into said heating flue through said top chimney opening in substantialy solely a vertical direction during rich gas opera-tion, and a third passage through said deck opening into the bottom of said flue at a point horizontally oilset frorn said first mentioned opening, said third passage being adapted to supply rich gas to said flue in substan tially solely a vertical direction during rich gas operation.

10. The combination defined in claim 9, further comprising means for regulating the size of said first mentioned opening and said top opening in said chimney.

11. A compound gun flue coke oven battery adapted to operate alternatively on rich gas and on lean gas, said coke oven battery comprising a plurality of spaced apart heating walls including a pair of spaced apart substantially uniformly thick heating wall liners with a multiplicity of vertically extending heating flues therebetween, a deck underlying said heating walls and coking chambers, a gun rflue for substantially each wall liner, said gun flues extending through said deck in substantial vertical alignment with said wall liners, substantially each of said heating flues having associated therewith a pair of passages extending upwardly through said deck between said gun flues, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, said deck opening being adapted to pass gaseous fluid therethrough in substantially solely a vertical direction, one of said pair of passages being adapted to supply lean gas to said heating flue during lean gas operation and to supply air to said heating flue during rich gas operation, the other of said pair of passages being adapted to supply air to said heating flue during both lean gas and rich gaS operation, a vertically extending chimney in said heating flue, said chimney having a top opening disposed substantially above the bottom of said heating flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas and air to a level substantially above the bottom of said heating flue and for introducing said mixed lean gas, air and their combustion products into said heating flue through said top chimney opening during lean gas operation and for conveying air to said level substantially above the bottom of said heating flue and for introducing said air into said heating flue through said top chimney opening in substantially solely a vertical direction during rich gas operation, a substantially solely vertically directed nozzle at the bottom of said heating flue, said nozzle being horizontally olfse-t from said opening in said deck, and a third passage extending through said deck and connecting said nozzle to one of said gun flues for supplying rich gas to said heating flue during rich gas operation.

12. The combination defined to claim 11, further comprising a first brick slidably movable into and out of overlying relation with said opening in said deck, and a second brick slidably movable into and out of overlying relation with said top chimney opening.

13. In a compound coke oven battery having a plurality of spaced apart coking chambers and a plurality of heating walls disposed therebetween, each of said heating walls comprising a pair of spaced apart heating wall liners and transversely extending spaced apart binders defining a multiplicity of vertically extending heating flues, and a deck underlying said heating walls and coking chambers; the combination with substantially each of said heating flues of a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, one of said pair of passages being adapted to supply lean gas to said heating flue and the other of said passages being adapted to supply combustion air to said heating flue, a chimney in said flue, said chimney being spaced from said heating wall liners, said chimney having a top opening disposed substantially above the bottom of said flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas and combustion air to a level substantially above the bottom of said flue and for introducing said mixed gas and air and their combustion products into said flue at said higher level through said top opening, and a third passage through said deck opening into the bottom of said flue at a point horizontally offset from said first mentioned deck opening, said third passage being adapted to supply rich gas to said heating flue.

14. In a compound coke oven battery having a plurality of spaced apart coking chambers and a plurality of heating walls disposed therebetween, each of said heating walls comprising a pair of spaced apart heating wall liners and transversely extending spaced apart binders defining a multiplicity of vertically extending heating flues, and a deck underlying said heating walls and coking chambers; the combination with substantially each of said heating flues of a pair of passages through said deck, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, one of said pair of passages being adapted to supply lean gas to said heating flue and the other of said passages being adapted to supply combustion air to said heating flue, a chimney in said flue, said chimney being spaced from said heating wall liners and being connected to one of said binders, said chimney having a top opening disposed substantially above the bottom of said flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas and combustion air to a level substantially above the bottom of said flue and for introducing said mixed gas and air and their combustion products into said flue at said higher level through said top opening, and a third passage through said deck opening into the bottom of said flue at a point horizontally ofiset from said first mentioned deck opening, said third passage being adapted to supply rich gas to said heating flue.

15. A compound gun flue coke oven battery adapted to operate alternatively on rich gas and on lean gas, said coke oven battery comprising a plurality of spaced apart heating walls including a pair of spaced apart substantially uniformly thick heating wall liners with a multiplicity of vertically extending heating flues therebetween, a deck underlying said heating walls and coking chambers, a gun flue for substantially each wall liner, said gun flues extending through said deck in substantially vertical alignment with said wall liners, substantially each of said heating flues having associated therewith a pair of passages extending upwardly through said deck between said gun flues, said pair of passages communicating with one another adjacent their upper ends and communicating with said heating flue through an opening in said deck, said deck opening being adapted to pass gaseous fluid thereth-rough in substantially solely a vertical direction, one of said pair of passages being adapted to supply lean gas to said heating flue during lean gas operation and to supply air to said heating flue during rich gas operation, the other of said pair of passages being adapted to supply air to said heating flue during both lean gas and rich gas operation, a vertically extending chimney in said heating flue, said chimney being spaced from said heating wall liners, said chimney having a top opening disposed substantially above the bottom of said heating flue, the bottom of said chimney overlying a portion only of said opening in said deck for conveying mixed lean gas and air to a level substantially above the bottom of said heating flue and for introducing said mixed lean gas, air and their combustion products into said heating flue through said top chimney opening during lean gas operation and for conveying air to said level substantially above the bottom of said heating flue and for introducing said air into said heating flue through said top chimney opening in substantially solely a vertical direction during rich gas operation, a substantially solely vertically directed nozzle at the bottom of said heating flue, said nozzle being horizontally oflset from said opening in said deck, and a third passage extending through said deck and connecting said nozzle to one of said gun flues for supplying rich gas to said heating flue during rich gas operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,873,077 Van Ackeren Aug. 23, 1932 1,999,780 Petsch Apr. 30, 1935 2,100,762 Becker Nov. 30, 1937 2,255,406 Becker Sept. 9, 1941 I 2,281,847 Koppers May 5, 1942 2,294,005 Taylor et al Aug. 25, 1942 FOREIGN PATENTS 1,021,567 France Feb. 20, 1953 

